She has found the perfect dress for her school prom – a beautiful jewel- studded number in nude chiffon. And, like every other teenage girl, Georgia Rankin can’t wait to show it off.

But while her friends fret about clashing dresses, 15-year-old Georgia is thrilled to know no one else be wearing hers... because it is made for a girl aged just three.

At just 80cm tall – just under 2ft 8in –Georgia is shorter than the average two-year-old and is believed to be Britain’s smallest teenager.

She has a a form of skeletal dysplasia which made her bones prematurely fuse as a toddler and she will never grow any bigger. And while she is in constant pain from the condition, Georgia remains impossibly optimistic and cheerful.

With infectious laughter, she tells me: “It’s my school prom coming up and me and friends have got a limo. I can’t wait. I have managed to get the perfect prom dress. I love it – it is so glamorous. This time it is an advantage being small. All my friends are fighting over prom dresses but nobody will have the same one as me.”

However with feet that take an infant size seven, wearing high heels has to remain just a dream for Georgia, from Warrington, Cheshire.

But while she is endearingly upbeat, Georgia and her parents Andrea and Simon have faced a lot in the last 15 years.

Her exact condition is so rare that it has never been officially diagnosed. Andrea explains: “Her X-rays were sent to other doctors across the world but nobody has been able to pinpoint it.”

It has been a long and difficult journey for the family. Andrea, 36, an admin assistant, and Simon, 38, a police officer, first knew something was wrong soon after Georgia was born when she started to lose weight and couldn’t keep food down.

Andrea says: “It was so scary when we first had Georgia. I was only 21 and she was our first baby and we didn’t know what was wrong. She was constantly undergoing tests and biopsies and spent the first three years of her life in hospital.”

Georgia was finally diagnosed with a bowel condition called tufting enteropathy and, incredibly, she had to be drip-fed for the first 10 years of her life.

“She couldn’t mix with other children because she had no immune system so we didn’t socialise with other mums and other babies so I had no one to compare her size to” says Andrea.

It was only when Georgia was three and started pre-school sessions that her mum noticed how much smaller she was than the others. And alarm bells had begun to ring when Georgia had started to walk and seemed to be in terrible pain.

Andrea says: “They did all sorts of scans then told us that her bones were prematurely fused and she would never grow any bigger.

Happy family: pictured here at home in Warrington, Cheshire, with her family with Mum Andrea, dad Simon and four-year-old brother Brody, who is taller than his sister. (Image: Julian Hamilton/Daily Mirror)

“I just felt completely numb. Everything was spinning and I felt like I was going to pass out. I had never heard of this and I just didn’t believe what they were telling me. I was in shock for a long, long time and I had a bit of anger as well.

“I would look at other mums and children and think my child is never going to grow like your child. I just wanted to wrap Georgia up and take her away.”

When she started school, Andrea worried about how Georgia would fare alongside other children her age.

“I didn’t want her to go and that was one of the hardest things I’ve ever had to do, standing in that playground on the first day, knowing she was never going to grow.

“When she started she didn’t stand out that much because there were some other little ones. But even then people were staring and I noticed other mums nudging each other. I remember thinking that this was what it was always going to be like.”

But while some may still stare, life for the family now is very different from their initial fears – especially when doctors at first thought Georgia’s life expectancy would be no more than 10-14 years. Now they believe she should live a normal life.

But Andrea can’t help noticing the things Georgia has missed, especially watching her four-year-old brother Brody, who is already taller than his sister.

“Brody had his first swimming lesson last week and I really relished that moment because it was something Georgia couldn’t do. She missed out on so many little things like learning to ride a bike. Sometimes when Brody reaches a milestone like that it does make me stop and think.”

But for Georgia, now a confident, happy teen known to her friends as “Lil G”, the key to being happy is simple. “I just forget I am small, I just see myself as the same as everyone else,” she says. “I don’t know anything different. I have always been small. When I started school I didn’t notice I was different, it was only when I got a bit older that I realised.

“When I was younger I did get bothered by people staring at me, but now I am so much more confident. I don’t mind at all if people ask me questions.

“I have never been bullied at school but we were once at a caravan park and there were some older kids who said, ‘Look at her, she’s small’, and they kept saying it and saying it. They were being really mean and it did upset me. But my friends at school are amazing. They see past my disability, they just see me, Georgia, their friend.”

But it has been difficult. For two years Georgia has been confined to an electric wheelchair after the agony of walking became unbearable.

“She is in constant pain and has been on morphine and other drugs for two years,” says Andrea. “But she puts on this gorgeous smile every day and everyone admires her so much.”

Georgia refuses to feel sorry for herself. She says: “It’s been a bit rubbish as it affects everything like school work because it’s hard to concentrate when I’m in pain and even going out with my family. If you’re in pain you won’t feel as happy. I used to go horseriding and that was my life but I’ve had to stop now because of my hips. I’m hoping if the operation works I can go back and do it again.”

One thing that frustrates fashion queen Georgia is that she can’t use the same shops as her friends. Her huge wardrobe is packed with rows and rows of shoes and clothes in mini-sizes. All the latest trends of course.

“I love clothes and shoes. It’s frustrating not to be able to go to Topshop and Hollister like all my friends. Luckily River Island does a good children’s range which I love. They even do patterned leggings.”

Lil G: Georgia Rankin (Image: Julian Hamilton)

Her family are currently trying to raise £18,000 for a state-of-the-art SnapDragon wheelchair which will give her more freedom. But Andrea is unsure whether Georgia will ever be able to live totally independently.

She says: “It scares me to think of her on her own because she is so small she wouldn’t be able to defend herself. Also she can’t lift things because she lacks strength, so she can’t even lift the kettle to make a cup of tea.”

The family recently moved to an adapted house and Georgia’s room has its own bathroom, two sets of double wardrobes and a sitting room complete with flatscreen TV. It’s the envy of all her friends.

The only clues to her tiny size are the toddler-size bed and the rows of tiny shoes in pride of place in her wardrobe. Andrea says: “She has her own front door and eventually she could have her own kitchen so it’s like a self-contained flat. As far as I’m concerned she can stay here forever.”

For now though, Georgia is just concentrating on having fun with her friends and revising for her GCSEs.

“It doesn’t bother me at all being smaller,” she says. “In my head I am just like everybody else. I will go shopping, to the cinema, go to the chippy or on the bus. I can do whatever other teenagers do” she says.

“I might be small, but I am not going to let it stop me from doing anything I want to do. I will always give anything a go.”

Colin Bruce, consultant orthapaedic surgeon at Liverpool’s Alder Hey hospital, says: “Georgia is a very brave young lady and a wonderful person. Her treatment is progressing and our team is doing everything possible to help her and her family.”